Image processing apparatus, image processing method and image forming apparatus

ABSTRACT

An image processing apparatus comprises an input interface, a light source unit, a reading unit and a control unit. The input interface receives an input reading condition. The light source unit comprises a plurality of light sources which emit lights of different wavelengths. The reading unit reads an image on a sheet irradiated by the light of the light source unit. The control unit separately controls the quantity of the light emitted from each light source according to the reading condition input from the input interface.

FIELD

Embodiments described herein relate to an image processing apparatus, animage processing method and an image forming apparatus.

BACKGROUND

Scanner is known as one of the apparatuses for reading one or moresheets to generate digital data. In one kind of scanners, a plurality oflight sources are arranged to emit lights of different wavelengths. Thiskind of scanner is equipped with a Light Emitting Diode (LED) lightsource for emitting red light, an LED light source for emitting greenlight and an LED light source for emitting blue light. Colors reappearwhen the scanner reads the color images on a sheet. Thus, the scannercontrols each light source so as to irradiate the sheet with whitelight.

However, in recent years, a scanner is desired to be capable of changingthe quality of an image according to the preference of the user. Thus,in this scanner, the chrominance of a light source needs to becontrolled according to the preference of the user. As the mainstream ofscanners is Auto Document Feeder (ADF) which is capable of reading bothsides of a sheet, in this scanner, the hue of a light source can bechanged for the surface and the back of a sheet.

The present invention is intended to provide an image processingapparatus, an image processing method and an image forming apparatuswhich are capable of reading an image corresponding to the preference ofthe user.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating the appearance of an image formingapparatus according to an embodiment;

FIG. 2 is a sectional view schematically illustrating the main structureof an image processing apparatus according to an embodiment;

FIG. 3 is a block diagram schematically illustrating the main structureof the control system of an image processing apparatus according to anembodiment;

FIG. 4 is a flowchart exemplifying the actions of an image processingapparatus according to an embodiment;

FIG. 5 is a diagram exemplifying a hue setting screen in an imageprocessing apparatus according to an embodiment;

FIG. 6A is a diagram exemplifying the light quantity control in an imageprocessing apparatus according to an embodiment; and

FIG. 6B is a diagram exemplifying another light quantity control in animage processing apparatus according to an embodiment.

DETAILED DESCRIPTION

In accordance with an embodiment, an image processing apparatuscomprises an input interface, a light source unit, a reading unit and acontrol unit. The input interface receives an input reading condition.The light source unit comprises a plurality of light sources which emitlights of different wavelengths. The reading unit reads an image on asheet illuminated by the light emitted from the light source unit. Thecontrol unit separately controls the quantity of the light emitted fromeach of the light sources according to the reading condition input fromthe input interface.

The image processing apparatus, the image processing method and theimage forming apparatus of the present invention are described belowwith reference to accompanying drawings.

FIG. 1 is a diagram illustrating the appearance of an image formingapparatus 1 according to an embodiment. An image forming apparatus 1 is,for example, a Multi-Function Peripheral (MFP). The image formingapparatus 1 reads, for example, one or more sheets to generate digitaldata. The image forming apparatus 1 forms an image with the generateddigital data. The sheet is, for example, paper on which an original,words or images is/are recorded, and any other object that can be readby the image forming apparatus 1. The sheet is hereinafter referred toas ‘original’.

The image forming apparatus 1 comprises an image reading apparatus 11(an image processing apparatus), a control panel unit 12 (an inputinterface), a printer unit 13 (an image forming unit) and a paper tray14. The image reading apparatus 11 reads the image on an original G. Theimage reading apparatus 11 outputs data (hereinafter referred to as‘read image data’) representing the read image (hereinafter referred toas ‘read image’) to the printer unit 13.

The control panel unit 12 functions as a user interface for receiving anoperation input by the user. The control panel unit 12 is equipped with,for example, a touch screen on which an operation section and a displaysection are integrated. The operation section of the control panel unit12 receives various instructions given to the image forming apparatus 1according to the operation of the user. The display section of thecontrol panel unit 12 displays various kinds of information for theuser. The information displayed is, for example, informationrepresenting the action status of the image forming apparatus 1. Thecontrol panel unit 12 may be equipped with operating buttons in additionto the touch screen. The touch screen of the control panel unit 12 maybe replaced by independent operation section and display section.

The printer unit 13 comprises a printer engine, an image processingsubstrate and a printer engine control substrate. The printer unit 13inputs the read image data output from the image reading apparatus 11.The image processing substrate of the printer unit 13 carries out animage processing for the read image data. The printer engine controlsubstrate of the printer unit 13 forms, on a sheet, an imagecorresponding to the read image data subjected to the image processing.The printer unit 13 is further capable of printing, on a sheet, an imageinput from an external device via a network. The printer unit 13 mayalso be an inkjet image forming apparatus, but not limited to an imageforming apparatus for fixing a toner image. The paper tray 14 is a traycapable of accommodating the sheet used by the printer unit 13.

Next, the image reading apparatus 11 serving as an image processingapparatus of an embodiment is described with reference to FIG. 2. FIG. 2is a sectional view schematically illustrating the main structure of animage processing apparatus according to an embodiment. The image readingapparatus 11 comprises a paper feeder 20 and an original reader 30.

The paper feeder 20 comprises an original feeding unit 21, a pickuproller 22, a resist roller 23, a belt transfer drum 24, a conveyanceroller 25, a back reading module 26 (a light source unit, a readingunit, a second light source unit and a second reading unit) and anoriginal discharging unit 27. The paper feeder 20 automatically feedsthe originals G held on the original feeding unit 21 to an originalimage reading position one by one. The paper feeder 20 is capable ofreading the image on the back of the automatically fed original G.

The original feeding unit 21 is a unit for accommodating the original Gconveyed by the paper feeder 20. A plurality of originals G can be heldon the original feeding unit 21. The pickup roller 22 is a drive rollerfor outputting the originals G on the original feeding unit 21 to theresist roller 23 one by one. The resist roller 23 is a drive roller foroutputting the original G fed from the pickup roller 22 to the belttransfer drum 24 at a given time.

The belt transfer drum 24 is a drum which conveys the original G fedfrom the resist roller 23 towards a secondary scanning direction D2 bywinding up the original G thereon and then rotating. The original G iswound on nearly half of the belt transfer drum 24. The conveyance roller25 is a roller which conveys the original G fed from the resist roller23 together with the belt transfer drum 24. A plurality of theconveyance rollers 25 are configured around the circumferentialdirection of the belt transfer drum 24.

The back reading module 26 which is configured on the back side of theoriginal G conveyed by the belt transfer drum 24 towards the secondaryscanning direction D2 reads an image on the back of the original G. Theback reading module 26 is provided with a light source unit including aplurality of light sources for emitting lights of different wavelengths.For example, the light source unit includes a red LED light source (afirst LED light source), a green LED light source (a second LED lightsource) and a blue LED light source (a third LED light source). The redLED light source emits red light. The green LED light source emits greenlight. The blue LED light source emits blue light. The back readingmodule 26 is equipped with a reading unit for reading an image on theback of an original G. For example, the back reading module 26 isprovided with a Charge Coupled Device (CCD) linear sensor in which a CCDelement is arranged in a primary scanning direction D1. The originaldischarging unit 27 is a unit for discharging the original G conveyed bythe belt transfer drum 24 towards the secondary scanning direction D2.

The original reader 30 comprises an ADF glass 31, an original stageglass 32, a white reference plate 33, a first carriage 34, a secondcarriage 35, a condensing lens 36, a CCD linear sensor 37 (a readingunit and a first reading unit), a CCD sensor substrate 38 and a controlsubstrate 39. The original reader 30 reads the image on the surface ofthe original G automatically fed by the paper feeder 20. The originalreader 30 reads the image on the side of an original G facing theoriginal stage glass 32, wherein the original G is placed on theoriginal stage glass 32 by the user.

The ADF glass 31 is a transparent plate glass arranged on the originalreader 30. The ADF glass 31 is located under the belt transfer drum 24of the paper feeder 20. The originals G sequentially conveyed by thebelt transfer drum 24 towards the secondary scanning direction D2successively pass the ADF glass 31. The position where the ADF glass 31is configured is the position where the original G conveyed by the paperfeeder 20 is read. The original stage glass 32 is a transparent plateglass arranged on the original reader 30. The original stage glass 32 islocated on the right side shown in FIG. 2 when compared with the ADFglass 31. The original G to be read without using the paper feeder 20 isplaced on the original stage glass 32 by the user.

The white reference plate 33 is a white plate providing a referencecolor for shading correction. The white reference plate 33 is arrangedon the original reader 30 and located between the ADF glass 31 and theoriginal stage glass 32. The white reference plate 33 is a plate-shapedcomponent having long sides and short sides. The long sides of the whitereference plate 33 are located along the primary scanning direction D1.That is, the short sides of the white reference plate 33 are locatedalong the secondary scanning direction D2.

The first carriage 34 comprises a light source unit 34 a (alight sourceunit, a first light source unit), a reflector 34 b and a first mirror 34c. The first carriage 34 is movably mounted on a track extending alongthe secondary scanning direction D2. When the original G automaticallyfed by the paper feeder 20 is read, the first carriage 34 is fixed underthe ADF glass 31, as shown in FIG. 2. When the original G placed on theoriginal stage glass 32 is read, the first carriage 34 moves below theoriginal stage glass 32 towards the secondary scanning direction D2.

The first carriage 34 emits light towards the upside. The first carriage34 reflects the light entering from above to the second carriage 35. Forexample, the first carriage 34 emits light towards the ADF glass 31. Thefirst carriage 34 reflects the light reflected by the original G passingthe ADF glass 31 to the second carriage 35. Alternatively, the firstcarriage 34 emits light towards the original stage glass 32 and reflectsthe light reflected by the original G on the original stage glass 32 tothe second carriage 35.

The light source unit 34 a faces the surface of the original G conveyedtowards the secondary scanning direction D2. The light source unit 34 aemits light upward obliquely. The light source unit 34 a has a pluralityof light sources which emit lights of different wavelengths. Forexample, the light source unit 34 a includes a red LED light source (afirst LED light source) for emitting red light, a green LED light source(a second LED light source) for emitting green light and a blue LEDlight source (a third LED light source) for emitting blue light. Thereflector 34 b reflects the light emitted from the light source unit 34a to the reflector 34 b upward obliquely. The first mirror 34 c reflectsthe light entering from above to the second carriage 35. For example,the first mirror 34 c reflects the light reflected by the original G onthe ADF glass 31 towards the second carriage 35. Alternatively, thefirst mirror 34 c reflects the light reflected by the original G on theoriginal stage glass 32 towards the second carriage 35.

The second carriage 35 comprises a second mirror 35 a and a third mirror35 b. The second carriage 35 is movably mounted on the same track withthe first carriage 34 and located on the left side of the first carriage34 shown in FIG. 2. When the original G automatically fed by the paperfeeder 20 is read, the second carriage 35 is fixed at the position shownin FIG. 2. When the original G placed on the original stage glass 32 isread, the second carriage 35 moves towards the secondary scanningdirection D2 matching with the movement of the first carriage 34. Thesecond carriage 35 reflects the light coming from the first carriage 34to the condensing lens 36. That is, the second mirror 35 a reflects thelight coming from the first carriage 34 down, and the third mirror 35 breflects the light reflected by the second mirror 35 a towards thecondensing lens 36.

The condensing lens 36 condenses the light reflected by the third mirror36 b to form the imaging on the illuminated surface of the CCD linearsensor 37. Like the CCD linear sensor of the back reading module 26, theCCD linear sensor 37 is a linear sensor in which a CCD element isarranged in the primary scanning direction D1. The CCD sensor substrate38 is a substrate on which a circuit for activating the COD linearsensor 37 to function is formed. The control substrate 39 is a substratefor a circuit which comprehensively controls the actions of the imagereading apparatus 11 to form a read image.

Next, the control system of the image reading apparatus 11 serving as animage processing apparatus of an embodiment is described with referenceto FIG. 3. FIG. 3 is a block diagram schematically illustrating the mainstructure of the control system of an image processing apparatusaccording to an embodiment. In FIG. 3, a control circuit for controllingthe back reading module 26 is not shown. The motor M shown in FIG. 3represents a motor for driving a drive system arranged in the imagereading apparatus 11. The drive system comprises a pickup roller 22, aresist roller 23, a belt transfer drum 24, a conveyance roller 25, afirst carriage 34 and a second carriage 35.

The control substrate 39 comprises a CPU 41 (a control unit), a timinggeneration circuit 42, an analog signal processing circuit 43, a linearmemory 44 and an image processing circuit 45. The control substrate 39has an address bus B1 and a data bus B2. In the control substrate 39,the CPU 41, the timing generation circuit 42, the analog signalprocessing circuit 43 and the processing circuit 45 are connected withthe address bus B1 and the data bus B2.

The CPU 41 comprehensively controls the actions of the image readingapparatus 11. For example, the CPU 41 controls the light source controlcircuit 61 to control the illumination of the light source unit 34 a.The CPU 41 also controls the illumination of the back reading module 26.The CPU 41 controls the timing generation circuit 42 to control thereading action of the CCD linear sensor 37. The CPU 41 controls theanalog signal processing circuit 43 and the image processing circuit 45to control an image processing performed on a signal obtained by the CCDlinear sensor 37. The CPU 41 further controls the reading action of theback reading module 26 and an image processing performed on a signalobtained by the back reading module 26. The CPU 41 controls a drivesystem control circuit 62 to control the actions of the paper feeder 20,the first carriage 34 and the second carriage 35.

The CPU 41 separately controls the quantity of the light emitted fromeach light source of the light source unit 34 a according to a readingcondition input into the control panel unit 12. That is, the CPU 41separately controls the quantity of the light emitted from each of thered LED light source, the green LED light source and the blue LED lightsource of the light source unit 34 a. The CPU 41 separately controls thequantity of the light emitted from each light source of the back readingmodule 26 according to a reading condition input into the control panelunit 12. That is, the CPU 41 separately controls the quantity of thelight emitted from each of the red LED light source, the green LED lightsource and the blue LED light source of the back reading module 26. TheCPU 41 separately controls the quantity of the light emitted from eachlight source of the light source unit 34 a and that of the light emittedfrom each light source of the back reading module 26.

When the white reference plate 33 is read, the CPU 41 controls the lightsources so that the quantity of the light emitted from each of the lightsources is equal. For example, when the CCD linear sensor 37 reads thewhite reference plate 33, the CPU 41 carries out a control of equalizingthe quantities of the lights emitted from the light sources of the lightsource unit 34 a. When the back reading module 26 reads the whitereference plate 33, the CPU 41 carries out a control of equalizing thequantities of the lights emitted from the light sources of the backreading module 26.

The CPU 41 carries out the control when reading the white referenceplate 33 so as to read the white reference plate in a hue preferred bythe user. Generally, shading correction is a processing of correctingthe unevenness in light quantities of light sources. Thus, auser-preferred hue is corrected when the white reference plate 33 isirradiated by light having the user-preferred hue and a shadingcorrection is carried out. To avoid this situation, the CPU 41 controlsthe light sources so that the quantity of the light emitted from each ofthe light sources is equal.

Under the control of the CPU 41, the timing generation circuit 42generates various timing signals for use by the image reading apparatus11. For example, the timing generation circuit 42 generates signals fordriving the CCD linear sensor 37 and the CCD linear sensor of the backreading module 26. The signals for driving the CCD linear sensors areshifting gate signals (SH signals) and transmit clocks. The timinggeneration circuit 42 generates a signal for activating the analogsignal processing circuit 43.

The analog signal processing circuit 43 processes the signals (analogsignals) obtained from the CCD linear sensor 37 and the CCD linearsensor of the back reading module 26. The linear memory 44 is a memoryfor the data corresponding to a thread read by the CCD linear sensor 37and the CCD linear sensor of the back reading module 26. The linearmemory 44 corrects the offset in the reading position of the CCD linearsensor.

Under the control of the CPU 41, the image processing circuit 45processes the data read by the CCD linear sensor 37 and the CCD linearsensor of the back reading module 26. For example, the image processingcircuit 45 corrects the offset in the reading position of the CCD linearsensor with the linear memory 44. The image processing circuit 45carries out a shading correction processing, an LOG conversionprocessing and other processing.

In addition to the CCD linear sensor 37, the CCD sensor substrate 38further comprises a sensor control circuit 51 and a sensor drive circuit52. The sensor control circuit 51 controls the actions of the CCD linearsensor 37 using the various timing signals output by the timinggeneration circuit 42 of the control substrate 39. For example, thesensor control circuit 51 adjusts the reading timing of the CCD linearsensor 37 using a timing signal output by the timing generation circuit42. Under the control of the sensor control circuit 51, the sensor drivecircuit 52 drives the CCD linear sensor 37. The sensor control circuit51 may also be arranged in the timing generation circuit 42.

Under the control of the CPU 41, the light source control circuit 61causes the light source unit 34 a to emit light or stop emitting light.Under the control of the CPU 41, the light source control circuit 61controls the quantity of the light emitted from each of the red LEDlight source, the green LED light source and the blue LED light sourceof the light source unit 34 a. For example, the light source controlcircuit 61 separately controls the currents supplied to the red LEDlight source, the green LED light source and the blue LED light sourceof the light source unit 34 a and controls the quantity of the lightemitted from each of the light sources. The light source control circuit61 separately controls the illumination time and the light quantity ofeach of the red LED light source, the green LED light source and theblue LED light source of the light source unit 34 a through a pulsewidth control. Under the control of the CPU 41, the drive system controlcircuit 62 controls the motor M for driving the paper feeder 20, thefirst carriage 34 and the second carriage 35.

Next, the actions of the image reading apparatus 11 serving as an imageprocessing apparatus of an embodiment are exemplified with reference toFIG. 4. FIG. 4 is a flowchart exemplifying the actions of an imageprocessing apparatus according to an embodiment. The processing shown inthe flowchart of FIG. 4 is started with the setting of a readingcondition by the user for the image reading apparatus 11 through anoperation on the control panel unit 12.

When the processing is started, a hue setting screen is displayed on thecontrol panel unit 12 for the setting of a hue corresponding to theoperation of the user (Act 11). The hue setting screen is a screen forthe user to set a hue when an original G is read by the image readingapparatus 11. FIG. 5 is a diagram exemplifying a hue setting screen inan image processing apparatus according to an embodiment. The huesetting screen exemplified in FIG. 5 has three sliders SL1-SL3.

The sliders SL1-SL3 set three primary colors of light at one end thereofand complementary colors of the three primary colors at the other endthereof. Specifically, the slider SL1 sets red, one of the three primarycolors of light, at one end thereof and the complementary color for redcolor, that is, cyan, at the other end thereof; the slider SL2 setsgreen, one of the three primary colors of light, at one end thereof andthe complementary color for green, that is, magenta, at the other endthereof; and the slider SL3 sets blue, one of the three primary colorsof light, at one end thereof and the complementary color for blue, thatis, yellow, at the other end thereof.

If the user slides the slider SL1 to the left side (the side of red)shown in FIG. 5, then the hue becomes strong in red. Contrarily, if theuser slides the slider SL1 to the right side (the side of cyan) shown inFIG. 5, then the hue becomes strong in cyan. If the user slides theslider SL2 to the left side (the side of green) shown in FIG. 5, thenthe hue becomes strong in green. Contrarily, if the user slides theslider SL2 to the right side (the side of magenta) shown in FIG. 5, thenthe hue becomes strong in magenta. If the user slides the slider SL3 tothe left side (the side of blue) shown in FIG. 5, then the hue becomesstrong in blue. Contrarily, if the user slides the slider SL3 to theright side (the side of yellow) shown in FIG. 5, then the hue becomesstrong in yellow.

In the case where only one side of an original G is read, only one huesetting screen exemplified in FIG. 5 is displayed on control panel unit12. For example, when only the surface of an original G is read, a huesetting screen for the surface of the original G is displayed on thecontrol panel unit 12. In the case where both sides of an original G areread, the hue setting screens exemplified in FIG. 5 are displayed on twocontrol panel units 12. Specifically, a hue setting screen for thesurface of the original G and a hue setting screen for the back of theoriginal G are displayed on the control panel unit 12. The user canseparately set the hues of the surface and the back of the original Gbased on the two hue setting screens displayed on the control panel unit12.

Here, it is assumed that the user slides the slider SL1 to the left side(the side of red) shown in FIG. 5 on the hue setting screen for the backof an original G and carries out no operation on the hue setting screenfor the surface of an original G. The content set on the hue settingscreen is output from the control panel unit 12 to the CPU 41 when theuser operates a start button after operating the hue setting screen.Moreover, the image reading apparatus 11 starts to read the original G(Act 12).

When the reading of the original G is started, first, each light sourceof the light source unit 34 a and each light source of the back readingmodule 26 are controlled to emit lights in the same quantity (Act 13).Specifically, the CPU 41 separately outputs control signals to the lightsource control circuit 61 and the back reading module 26. Moreover, thered LED light source, the green LED light source and the blue LED lightsource of the light source unit 34 a are controlled so as to beequalized in light quantity by the light source control circuit 61.Moreover, the red LED light source, the green LED light source and theblue LED light source of the back reading module 26 are controlled so asto be equalized in light quantity by the back reading module 26.

FIG. 6A is a diagram exemplifying the light quantity control in an imageprocessing apparatus according to an embodiment. In FIG. 6A, the curveL1 is a curve representing the wavelength characteristic of the lightemitted from a red LED light source. The curve L2 is a curverepresenting the wavelength characteristic of the light emitted from agreen LED light source. The curve L3 is a curve representing thewavelength characteristic of the light emitted from a blue LED lightsource. Subsequent to the start of the reading of the original G, thered LED light source, the green LED light source and the blue LED lightsource are controlled so that the light quantity in each centralwavelength is equal.

Next, a processing of reading the white reference plate 33 is executed(Act 14). Specifically, the CPU 41 controls the motor M to move thefirst carriage 34 to be below the white reference plate 33, therebyirradiating the back of the white reference plate 33 with the lightsthat are emitted from the light source unit 34 a and controlled to beequal in quantity. Moreover, the CCD linear sensor 37 reads the back ofthe white reference plate 33. The surface of the white reference plate33 is irradiated by the lights that are emitted from the back readingmodule 26 and controlled to be equal in quantity. Moreover, the backreading module 26 reads the surface of the white reference plate 33.

After the data read by the CCD linear sensor 37 from the white referenceplate 33 is processed by the analog signal processing circuit 43, thedata is input to the image processing circuit 45 for shading correction.After the data read by the back reading module 26 from the whitereference plate 33 is processed by the analog signal processing circuit43, the data is input to the image processing circuit 45 for shadingcorrection.

Sequentially, each light source of the light source unit 34 a and eachlight source of the back reading module 26 are controlled according tothe content set on the hue setting screen of the control panel unit 12(Act 15). As it is assumed here that the user carries out no operationon the hue setting screen for the surface of an original G, the red LEDlight source, the green LED light source and the blue LED light sourceof the light source unit 34 a are controlled so as to be equalized inlight quantity by the light source control circuit 61. Specifically, thered LED light source, the green LED light source and the blue LED lightsource are controlled so that the light quantity in each centralwavelength is equal, as shown in FIG. 6A.

Here, it is considered that the user slides the slider SL1 to the leftside (the side of red) shown in FIG. 5 on the hue setting screen for theback of an original G. Thus, the red LED light source, the green LEDlight source and the blue LED light source of the back reading module 26are controlled so that the light quantity of the red LED light source isrelatively larger. FIG. 6B is a diagram exemplifying another lightquantity control in an image processing apparatus according to anembodiment. In FIG. 6B, curves L1, L2 and L3 are curves representing thewavelength characteristics of the lights emitted from a red LED lightsource, a green LED light source and a blue LED light source.

In the example shown in FIG. 6B, a first control is carried out toreduce the light quantities of the green LED light source and the blueLED light source. Through the first control, the light quantity of thered LED light source is relatively larger than those of the green LEDlight source and the blue LED light source. A second control contrary tothe first control may be carried out to increase the light quantity ofthe red LED light source. Through the second control, the light quantityof the red LED light source is also relatively larger than those of thegreen LED light source and the blue LED light source. Another control ofincreasing the light quantity of the red LED light source whiledecreasing those of the green LED light source and the blue LED lightsource is also applicable.

Then, a processing of reading the original G is carried out (Act 16).First, the CPU 41 controls the motor M to move the first carriage 34 tobe below the ADF glass 31. Sequentially, the CPU 41 controls the motor Mto rotate the pickup roller 22, the resist roller 23, the belt transferdrum 24 and the conveyance roller 25. In this way, the originals G heldon the original feeding unit 21 are picked up one by one. The original Gfed from the pickup roller 22 is output to the belt transfer drum 24 bythe resist roller 23 at a given time.

The original G output to the belt transfer drum 24 is conveyed on theADF glass 31 towards the secondary scanning direction D2 while beingwound on the rotating belt transfer drum 24. Then, the light reflectedfrom the surface of the original G passing the ADF glass 31 is read bythe linear sensor 37. Meanwhile, the light reflected from the back ofthe original G conveyed in the secondary scanning direction D2 is readby the back reading module 26. The image processing circuit 45 performsan image processing on the data read by the linear sensor 37 and thedata read by the back reading module 26. The data subjected to the imageprocessing is output to the printer unit 13 as read image data.Moreover, an image corresponding to the read image data is formed on asheet by the printer unit 13.

As stated above, the image processing apparatus of the embodimentacquires a reading condition input from an input interface. The imageprocessing apparatus separately controls the quantities of the lightsemitted from a plurality of light sources emitting lights of differentwavelengths according to the reading condition. The image processingapparatus reads an image from a sheet illuminated by the lights emittedfrom the light sources which are separately controlled in lightquantity. As a result, the image can be read in a user-preferred hue.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the invention. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinvention. The accompanying claims and their equivalents are intended tocover such forms or modifications as would fall within the scope andspirit of the invention.

1. An image processing apparatus, comprising: a processor that executesinstructions to perform operations comprising: receiving a hue setting;emitting light of different wavelengths using a light source unitequipped with a plurality of light sources; reading an image on a sheetirradiated by light emitted from the light source unit; and controllinga quantity of the light emitted from each of the light sources based onthe hue setting.
 2. The image processing apparatus according to claim 1,further comprising: a white reference plate for shading correction,wherein the operations further comprise: controlling each of the lightsources so that the quantity of the light emitted from each of the lightsources is equal when the white reference plate is read.
 3. The imageprocessing apparatus according to claim 1, wherein the light source unitcomprises a first light source section located on a first side of asurface of a sheet and a second light source section located on a secondside of a back of the sheet; and wherein the operations furthercomprise: reading an image on the surface of the sheet illuminated bylight emitted from the first light source section, and reading an imageon the back of the sheet illuminated by light emitted from the secondlight source section.
 4. The image processing apparatus according toclaim 3, wherein the operations further comprise: separately controllinga quantity of light emitted from each light source comprising the firstlight source section and a quantity of light emitted from each lightsource comprising the second light source section.
 5. The imageprocessing apparatus according to claim 3, wherein the first lightsource section and the second light source section both include a firstLED light source for emitting red light, a second LED light source foremitting green light and a third LED light source for emitting bluelight.
 6. The image processing apparatus according to claim 5, whereinthe operations further comprise: separately controlling current suppliedto the first LED light source, the second LED light source, and thethird LED light source and the quantity of the light emitted from eachof the first LED light source, the second LED light source, and thethird LED light source.
 7. The image processing apparatus according toclaim 5, wherein the operations further comprise: separately controllingan illumination time and a light quantity emitted by each of the firstLED light source, the second LED light source, and the third LED lightsource through a pulse width control.
 8. An image processing method,comprising: acquiring, by a system comprising a processor, a hue settinginput from an input interface; separately controlling, by the system, aquantity of light emitted from each of a plurality of light sourcesemitting light of different wavelengths based on the hue setting; andacquiring, by the system, an image on a sheet irradiated by lightemitted from the plurality of light sources.
 9. The image processingmethod according to claim 8, wherein each of the plurality of lightsources is controlled, by the system, to emit light in a same quantitybefore the image on the sheet is read, not rigidly adhering to the huesetting; and a white reference plate is read and used for shadingcorrection.
 10. An image forming apparatus, comprising: the imageprocessing apparatus according to claim 1; and wherein the operationsfurther comprise: forming an image according to image data of a sheetread by a reading unit of the image processing apparatus.
 11. The imageprocessing apparatus according to claim 1, wherein the operationsfurther comprise: displaying a hue setting screen on a control panelunit of a input interface.
 12. The image processing apparatus accordingto claim 11, wherein the operations further comprise: displaying atleast a slider as the hue setting screen on the input interface.
 13. Theimage processing apparatus according to claim 12, wherein the operationsfurther comprise: displaying at least one of three primary colors near afirst end of the slider and at least one of complementary colors near asecond end of the slider, the second end being opposite the first end.14. The image processing apparatus according to claim 11, wherein theoperations further comprise: displaying only one hue setting screen onthe input interface in a case of reading only one side, and displayingtwo hue setting screens on the input interface in a case of reading bothsides.